Winter is coming... Time to start GM70 SE parafeed amp - Page 3 - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 12th October 2013, 08:48 AM   #21
diyAudio Member
 
Shoog's Avatar
 
Join Date: Aug 2002
Location: Eire
Quote:
Originally Posted by grimtale View Post
As a ham radio operator for decades, I've worked on a lot of RF amplifiers. Once worked on one with 7500v on the plate.
I got shocked once on a 1800v amp. I was shorting the caps to ground before servicing it and the voltage jumped through the insulation on the screwdriver, ran through my arm and popped open a 1/4" opening on my elbow...
Be careful
Mark
Remember our bones are made of conductive metal (calcium).
I backed away from anything approaching 1000V a long time ago, my limit is 400V.

Shoog
  Reply With Quote
Old 12th October 2013, 09:17 AM   #22
diyAudio Member
 
Join Date: Nov 2010
Quote:
Originally Posted by Shoog View Post
Remember our bones are made of conductive metal (calcium).
I backed away from anything approaching 1000V a long time ago, my limit is 400V.

Shoog
I guess some biology lesson would do you good

Our bones are not made from Calcium but a Calciumsalt.
  Reply With Quote
Old 12th October 2013, 09:45 AM   #23
M Gregg is offline M Gregg  United Kingdom
diyAudio Member
 
M Gregg's Avatar
 
Join Date: Jun 2010
Location: UK
Most of the shock current,

tends to flow in the bone marrow / body fluid. The more current that flows the more burning creating carbon the pressure can build up and split/ break the bone, current increases etc. The skin resistance is the main protection but breaks down very quickly. Its very hard to completely isolate yourself from current return because the ground you stand on is Earth and resistance of shoe souls etc have an impact.

However back to topic .

Regards
M. Gregg
__________________
What is the sound of one hand clapping?
  Reply With Quote
Old 12th October 2013, 10:05 AM   #24
diyAudio Member
 
Join Date: Dec 2005
Location: Plymouth, England
Quote:
Originally Posted by yagoolar View Post
finger touch or proximity activated
Having just read all this thread, proximity activated is looking better and better!
  Reply With Quote
Old 12th October 2013, 10:15 AM   #25
diyAudio Member
 
yagoolar's Avatar
 
Join Date: Oct 2004
Location: Mazowieckie, Jozefoslaw
Send a message via ICQ to yagoolar Send a message via Skype™ to yagoolar
Quote:
Originally Posted by awkwardbydesign View Post
Having just read all this thread, proximity activated is looking better and better!
Like!
+1
  Reply With Quote
Old 12th October 2013, 10:56 AM   #26
diyAudio Member
 
yagoolar's Avatar
 
Join Date: Oct 2004
Location: Mazowieckie, Jozefoslaw
Send a message via ICQ to yagoolar Send a message via Skype™ to yagoolar
Gentlemen,
Thank you for all your remarks. Especially for those concerning HV.

Appreciate it.
  Reply With Quote
Old 12th October 2013, 02:36 PM   #27
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
I think we've covered the risks involved at these voltages pretty well, it's manageable with awareness. Let's get back on topic and talk about amplifier design.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 12th October 2013, 03:30 PM   #28
diyAudio Member
 
yagoolar's Avatar
 
Join Date: Oct 2004
Location: Mazowieckie, Jozefoslaw
Send a message via ICQ to yagoolar Send a message via Skype™ to yagoolar
My intention WAS to invoke discussion about 1kV experiences.
  Reply With Quote
Old 13th October 2013, 06:11 PM   #29
diyAudio Member
 
Join Date: Feb 2010
Quote:
Originally Posted by kevinkr View Post
I had the biggest problem with the copper version of the GM70, the graphite plate ones on hand seem to settle down quickly and permanently.
Probably because the copper ones are, by and large, older. Ulyanov stopped manufacturing the copper plates in the early '80s, while they made Graphites right up until 1994.
BTW, the only trouble I've had with either was a copper plate, (but it was just one).

Strangely, the steel plate GM-70, which Foton haven't made since the '50s, don't seem to give anyone (lucky enough to have them) any trouble.
I've had the pleasure of borrowing a pair to "break them in" for a client, and they settled in quite admirably. I wish I could afford a pair! (They seem to have the "best of both worlds" the copper plate's magic mids and the graphite's extended bottom).
  Reply With Quote
Old 14th October 2013, 09:25 AM   #30
diyAudio Member
 
Vincent77's Avatar
 
Join Date: Jan 2011
Location: Bruxelles
I've compared graphite plates to copper plates in my amp. While the graphites have stronger bass indeed, I prefer the copper's lush mids...
I've had some trouble too with copper plates and they are quite expensive. I wasn't even aware that steel plates existed...
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
FINALLY I can start building my GM70 djn Tubes / Valves 47 5th November 2013 06:01 AM
GM70 SE Amplifier gabrielbecheanu Tubes / Valves 35 18th July 2011 04:01 AM
Well, it is time to start thinking about winter projects. GM70 djn Tubes / Valves 14 17th August 2010 08:49 AM
GM70/GM70 parafeed SET? louischia Tubes / Valves 10 4th December 2008 03:12 PM
Soft start & Dead time for TL494 ifrythings Power Supplies 9 18th May 2008 08:31 PM


New To Site? Need Help?

All times are GMT. The time now is 03:57 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2